A user equipment (UE) in a wireless communication system is able to receive data and/or various control informations in downlink (DL) from a base station (BS) and is also able to transmit data and/or various informations in uplink (UL). In order for a UE to communicate with a BS, the UE should be synchronized with the BS. To this end, if a turned-off power of the UE is turned on again or the UE newly enters a cell corresponding to a geographical region serviced by the BS, the UE performs an initial cell search accompanied with a job such as matching a synchronization with the BS or the like. Having finished the initial cell search, the UE is able to receive data and/or control information through a physical downlink channel and is also able to transmit data and/or control information through a physical uplink channel.
Due to various reasons such as a cell search, a maintenance of time synchronization after synchronization between UE and BS, a correction of frequency offset and the like, a wireless communication system discussed so far defines that various mandatory signals should be transmitted/received on designated radio resources.
Types and amounts of the mandatory signals have increased owing to the developments of standards of the corresponding wireless communication system. Since it is unable to assign a different signal to a radio resource to which a corresponding mandatory signal is assigned, mandatory signals increasing owing to the development of the corresponding wireless communication system hinder the degree of freedom in the scheduling of the corresponding wireless communication system and impose restrictions of the introduction of an efficient communication technology into the corresponding wireless communication system.